Wet-treating fibrous matters



March 24, 1953 s. E. E. AHLFORS 2,632,366

WET-TREATING FIBROUS MATTERS Filed July 8, 1946 a Sheets-Sheet 2 w 44 25 45 I; l 4 7 M I u I 5720 22 522? 2o March 24, 1953 s. E. E. AHLFORS 2,632,366

WET-TREATING FIBROUS MATTERS Filed July 8, 1946 3 Sheets-Sheet 3 Patented Mar. 24, 1953 WET-TREATING FIBROUS MATTERS Sten Eskil Einarsson Ahlfors, Hedemora, Sweden Application July 8, 1946, Serial N 0. 682,021 In Sweden July 11, 1945 3 Claims.

This invention relates to apparatus for wettreating fibrous substances, particularly for straining, classifying, dewatering, washing and similar treatments of liquid suspensions of fibres, such as paper pulp.

One of its objects is to provide an improved apparatus for performing a vibratory method of wet-treating fibrous substances resulting in maximum output per unit area of an apertured member forming a basic element of the apparatus.

Another object is to provide simple and effective means for varying the pulsating pressure to which the suspension undergoing vibratory treatment is subjected, to suit different characteristics of the fibrous suspension, as well as varying conditions of operation.

Still another object is to utilize effectively the phenomena of resonance and beating in wettreating fibrous substances.

The invention comprises the novel means hereinafter fully described and particularly pointed out in the claims hereunto appended.

The invention is illustrated by way of example on the annexed drawing in which:

Fig. 1 shows a side elevation of a strainer according to one embodiment of the invention.

Fig. 2 shows a central longitudinal section substantially along line II-II in Fig. 3.

Figs. 3 and 4 show transverse sections substantially along lines IIIIII and IV-IV respectively in Fig. 1.

Fig. 5 shows a side elevation of a strainer embodying a second form of the invention, a gearing associated with the vibratory apparatus of the strainer being shown somewhat diagrammatically.

Fig. 6 shows an end elevation of said strainer as viewed from the right-hand end of Fig. 5.

Fig. '7 shows a longitudinal section substantially along line VII-VII in Fig. 6.

Fig. 8 shows a transverse section substantially along line VIII-VIII in Fig. 7.

Fig. 9 is a side elevational view of a modified embodiment.

Fig. 10 is an end view partly in section of said modified embodiment.

Fig. 11 is a longitudinal central sectional view of said modified embodiment.

Referring to Figs. 1-4 the embodiment illustrated therein comprises generally two vats l and. 2 the latter of which has an apertured curved strainer element 3 rigidly secured thereto and constituting the bottom thereof. Clamped tothe lower marginalportion of vat 2 and to the upper marginal portion of vat I is a flexible diaphragm 4 permitting limited relative movement of vats I and 2.

Vat l is formed with leg members 5 apertured at their bottom ends as indicated at 6 in Fig. 1 forming bridge members I resting against resilient or elastic members 8, such as springs or rubber pads united to metal plates at the top and bottom face of each pad, and carried by bed plates 9 supported by a foundation diagrammatically indicated at I0. Resting on the top face of each bridge member I is a second resilient or elastic member I l of similar construction in contact with a bridge member I2 adjustably mounted on bolts [3 rising from bed plates 9. Carried by the upper ends of bolts [3 are nuts M by means of which the pressure exerted by bridge members 12 against members II and thus against members 8 through the agency of bridge members I may be varied at will to adjust the resiliency or elasticity of means 8, H and thus the damping of vat I when vibrated as set forth in the following.

Strainer vat 2 is resiliently supported by vat i in a manner now to be described.

Resting on brackets l5 laterally projecting from vat I are coil springs I6 compressed by means of washers ll slidably mounted on rods l8 depending from tubular members 33 passing longitudinally through vat 2, Threaded on rods [8 are nuts l9 by means of which the compression of springs It may be varied at will. Similar means comprising coil springs l6, washers I! and nuts l9 are mounted below brackets l5 and by this means and the equivalent means above brackets [5 the movement of vat 2 when vibrated as set forth in the following may be controlled to some extent. As clearly shown in Fig. 3 rods I8 have sufiicient lateral play in brackets IE to permit any desired lateral movement of vat 2 when vibrated.

Suspended by rods I8 is a vibratory apparatus comprising two double bearings 20 clamped at opposite sides between nuts 34 threaded on rods I8 as may be clearly seen from Fig. 1. Journalled in said bearings are two rotary shafts 2i each carrying two unbalanced or eccentrically arranged masses 22 serving to vibrate strainer vat 2 when shafts 2| are rotated. In the embodiment shown the rotation of shafts 2! is effected from an electric motor 23 by means of a shaft 24 connected to motor 23 and one of shafts 2| by means of flexible couplings 25, shafts 2i being interconnected by a suitable spur gearing (not shown). By this means shafts 2| are rotated in mutually opposite directions whereby the horizontal forces from the rotating unbalanced masses 22 may be caused to neutralize each other to secure a substantially rectilinear vertical vibratory movement. Alternatively the form and inclination of the elliptical orbit of vibration may be varied at will by mounting unbalanced masses 22 of different sizes on each of said shafts 2| to suit any requirements met in practice. The vibratory movement from the vibratory apparatus is preferably applied to strainer vat 2 including strainer element 3 symmetrically to its center of gravity and pressure when loaded by the suspension to be treated and moving therein.

The embodiment of my improved strainer above described operates as follows.

The fibrous suspension to be treated is supplied to the strainer vat 2 at any suitable point, such as at A in Figs. 1 and 2 from any suitable supply diagrammatically illustrated as a launder 26 with adjustable outlet 2? permitting a control of the incoming suspension so as to maintain a suitable level of liquid in strainer vat 2 as indicated at L in Fig. 2. The suspension thus introduced tends to pass through the apertured strainer element 3 which together with the body of strainer vat 2 is caused to vibrate rapidly by means of the vibratory apparatus above described. This vibration is effected directly mechanically from the vibratory apparatus While the lower vat I is indirectly vibrated firstly hydraulically from strainer element 3 through the agency of the liquid of the suspension undergoing treatment and secondly mechanically byv adjustable forces applied from vat 2 over springs it, the vibration of vat I being possible due to the mode of resiliently supporting and clamping vat l by means of elements 8, H, l2, l3 and I4 as described in the foregoing. The vibration of vat I will take place at a considerably smaller amplitude than that of vat 2, due to the relatively loose coupling through the liquid I, the inertia of vat i and the damping produced by elements 8 and H. According to the foregoing such damping may be easily adjusted to control the difference-of amplitude between vats l and 2 and thus the pulsating pressure produced in the liquid between said vats.

The liquid of suspension and accompanying solids passing through strainer element 3 is continuously discharged at B into a suitable receiver shown as a launder 28 provided with a tubular stud 29 connected to a tubular stud 30 at the right-hand bottom end of vat I by means of a flexible tubular member 3! permitting vat 2 to vibrate.

The liquid of suspension and accompanying solids rejected by strainer element 3 is continuously discharged from vat 2 at C and received by launder 32.

The embodiment shown in Figs. -8 differs generally from that above described in that only one vat 2 is used the bottom of which is vibrated directly from a vibratory apparatus similar to that described with reference to the first embodiment whereas strainer element 3 is vibrated indirectly through the agency of the liquid of the suspension undergoing treatment. For the remainder the two embodiments are generally similar and it appears, therefore, sufiicient to describe the detailed construction of the second embodiment merely in the respects in which it differs fromthe first embodiment, similar reference characters being used in all of the figures of the drawing to represent corresponding parts.

As indicated above, in the second embodiment the vibratory apparatus is associated with the bottom of vat 2 which to this end is connected to to the body of said vat by means of a flexible diaphragm 4 clamped between upper and lower plates 39 and 46 respectively. Suspended from plate it by means of channel irons is' the vibratory apparatus the two double bearings 29 of which are bolted to channel irons 4| and to plate ll! as shown diagrammatically on the drawing.

Vat 2 is resiliently supported from bed members 42 by means of resilient or elastic, preferably replaceable members 8 clamped to vat 2 and to members 42 by threaded bolts 36.

Raising from bed members 42 are standards l8 clamped at their bottom ends to members 42 by nuts 43. Surrounding standards l8 are lower coil springs l5 resiliently supporting channel irons 54 secured to channel irons 5i and resting on said springs I6 by means of washers 45. Although not specifically shown standards 48 have lateral play in elements fi l-46 just as rods [8 the first embodiment have lateral play in br ets 15. Similarly upper springs l5 surrgund st ards 18 above channel irons M- and rest aga st washers 36 in contact with the top face of channel irons 4. The tension of coil springs I5 may be varied simply by adjusting nuts 9 to suitany requirements met in practise as regards the Yi'. brations imparted to plates 39;, 459 by the vibratory apparatus.

As to the latter it may here be mentioned that the gearing interconnecting shafts 21 and not shown in the first embodiment has been illustrated diagrammatically at 37 in Figs. .5-.7.

As may be seen from Figs. 5 and 6 the upper ends of standards i8 are clamped together by channel irons 41 secured between nuts 48 at the top of standards 58. By this means nondesired, lateral movements of standards I8 and the elements associated therewith are prevented. Be sides, channel irons 41 may be utilized to control the damping of vat 2 by adjusting nuts 48 whereby elastic or resilient members, such as iron clad rubber pads [I may be pressed by any desired force against brackets 59 laterally projecting from vat 2 as clearly shown in Fig. .6.

As to the operation of the second embodiment it appears sufiicient to mention that the fibrous suspension to be treated is supplied at A in Fig. 7 and tends to move upwards through aperturegl strainer element 3 which is caused to vibrate rapidly through the agency of the liquid o thesuspension from elements 4, 39, i0 vibrated directly from the vibratory apparatus. The matter passing through strainer element 3 is continuously discharged at the top face thereof .as indicated diagrammatically at B whereas the matter rejected by strainer element 3 is continuously discharged at the bottom face of element .3 as in.- dicated-at C through bell-shaped member 5] and central tube 52 mounted therein as may be glearly seen from the arrows in Figs. 7 and 8,. Further description of such discharge means appear .1" perfiuous as such means forms no part of my invention. 7

In the embodiment represented in Figs. 9,, .10, and 11, a single vat til is provided which di-v vided by a substantiallyhorizontalstrainer; ment 61 secured to the vat walls. rA-fiegr U phragm 62 is clamped atits-edgesibetween i r and lower plates 64 and -B.5 respectively. pended from plate 65 by securing armsl-BS, isla vibratory apparatus having double bearings 68.

The vibratory apparatuscinclude s a pairofldrive ed a pair of eccentrically arranged masses 10, 10.

Rapid turning of the drive shafts 69 and masses 1i] imparts to diaphragm a rapid vibration, which in turn is imparted to the substance contained in vat Hill. Gearing interconnecting the drive shafts is diagrammatically shown at 61. Vat 6B is mounted on resilient or elastic members H which in turn rest on fixed stationary bed plates 72, and the vat is prevented from becoming displaced by bolts M, which extend through portions 15 of the vat, the elastic members 'H, and the stationary plates 12, mounted on foundation 13.

On the upper edges of the vat 60 are mounted further double bearing members 68' which rotatably mount a pair of further drive shafts 69 which are geared together as diagrammatically represented at 57' to rotate in opposite directions. These drive shafts are each provided with a pair of eccentric masses Hi which impart rapid vibration motion to the vat 68 when the drive shafts 69' are rotated.

The vat E8 and lower plate 65 are resiliently interconnected by means of a set of coil springs l6 which are clamped between securing arms 56, mounted on lower plate 65, and washers 11 mounted on threaded rods 79, which are connected at their upper ends to brackets 80 on the sides of vat B0. The tension or compression in springs '56 can be adjusted by turning nuts 8! on the lower ends of rods 79.

Electric motors 84 and 85 are shown as the drive means for the shafts E9, 69', respectively. To allow for the vibrations of the vibratory members on which shafts 69, 69' are mounted, flexible couplings 86, 85 are interposed in the connections between the drive motors and the respective shafts.

In operations the vat E0 and diaphragm B2 are vibrated at mutually different rates. The fibrous suspension enters the vat at the point indicated by arrow A; liquid of suspension and solids passing the strainer leave by discharge B and the liquids of suspension and solids rejected by the discharge C.

Although in the embodiments above described the two elements are assumed to be vibrated by means of rotary shafts supporting unbalanced masses it is, of course, within the scope of my invention to effect the vibration by any other mechanical means, for instance, by eccentrics and pitmans positively vibrating either element, or by hydraulic, pneumatic, electric or magnetic means.

It is also within the scope of my invention to allow either element to vibrate at more or less pronounced resonance to amplify the vibrations as desired.

In the preferred embodiments of my invention the two elements are vibrated with mutually different amplitudes whereby the pulsating pressure acting upon the suspension between said elements may be increased or decreased simply by increasing or decreasing the difference in amplitude between said two elements. By vibrating both elements directly at equal frequency but in opposite phase the intensity of the pressure and suction impulses produced in the suspension between the two elements in response to the vibration thereof may be still more increased. By vibrating the two elements at mutually different frequencies recurrent pulsations of increased amplitude may be obtained according to the well known phenomenon of beating, such as for automatically cleaning the apertured element from fibrous sub-a stances tendin to clog therein.

From the foregoing it may be seen that I have invented a new method of wet-treating fibrous substances resulting in many advantages.

Before all, the output per unit area of the vibrating apertured element is materially increased by simultaneously differently vibrating the opposite non-perforated element in that both elements then act, positively on the suspension undergoing treatment.

Another advantage of my improved method resides therein that suspensions of relatively high fibrou contents may be continuously treated due to the more intense actin upon of the suspension in differently vibrating both elements.

Still another advantage of my invention will be clear when considering the 'dewatering or pumping effect produced in vibrating a strainer member having apertures presenting, unequal flow resistances in opposite directions, such as tapering apertures, such effect being dependent substantially on the amplitude of vibration of the strainer element. According to my invention this effect may be utilized to the best advantage in different treatments of the suspension. Thus, if dewatering to a large extent is desired this result may be secured according to my invention by vibrating the strainer element directly with sufficiently large amplitude and controlling the amplitude of vibration of the second element indirectly vibrated, to avoid excessive pulsating pressures in the suspension, On the other hand, if dewatering to a smaller extent is desired, then the strainer element may be vibrated indirectly with relatively small amplitude and the second element directly with sufficiently large amplitude to secure the required pulsating pressure in the suspension.

Although the invention in the foregoing has been specifically described in connection with straining of fibrous suspensions it may obviously be applied to other wet-treatments of such suspensions, such as to classifying, dewatering or washing. Th modifications of the method and apparatus then necessary are obvious to anyone familiar with the art.

What I claim is:

1. An apparatus for wet-treating fibrous substances, particularly for straining, classifying, dewatering and washing liquid suspensions of fibres, comprising means for supplying the suspension to be treated to said apparatus, a strainer vat having a strainer element rigidly secured thereto, a second vat situated therebelow and connected to said first mentioned vat by a flexible diaphragm, a rigid foundation, resilient means for supporting said second mentioned vat from said foundation, resilient means for supporting said first mentioned vat from said second mentioned vat, vibratory means suspended from said first mentioned vat and adapted to vibrate said strainer element and the part of said second mentioned vat mutu ally differently, so as to cause said suspension to partially pass through said strainer element, and means for discharging the part of said suspension passing through said strainer element at one face thereof and the part rejected by said strainer element at the opposite face thereof.

2. An apparatus of the class specified comprising in combination, a foundation, a vat having a yieldingly mounted rigid bottom, elastic means for supporting said vat on said foundation, a screen dividing the vat into a lower chamber and an upper chamber communicating with math other through theorifines of the screen, aninlet for -a suspension of fibrous material leading to said lower chamber, an outlet for *finer fibrous material leading irom said upper ohamber, an outlet for 'ooar's'er mate'rial leading from the lower chamber, springs for resiliently supporting the bottom of the vat, and vibratory means connected to the bottom of the vat for effecting a positive vibration of the'bottom and due to the resilient 1o mounting of the vat a vibration'of the bottom and the screen alta difierent amplitude than that of the vibration of the bottom so as to effect a .pulsatory pressure-in the "suspension between the 'bottom and the screen.

3. In aim-apparatus as claimed in 'c1aim'2,'the further 'fe'aturethat additional vibratory means are i-provided-in connection with the 'vat foriipositively controllin' the'amplitude of the vibration of the's'creen with relation to thatof the bottom. 20

S'IEN ESK-IL EINARSSON 'AHLFORS.

REEERENGES CITED The following references are of record in the file of this patent:

UNITED STATES PATEN T S Number Name Date 192,107 Blizzard June 19, 1877 498,041 White 'Ma 23, '1893 589,32!) iBetram Aug. 3,1897 682,839 Baker r Sept. 17,1901 2,276,631 Smith -QMar. 17, 1942 2,293,978 Jonsson Aug25f1942 FOREIGN PATENTS Number Country Date 24,904 Great Britain of'1898 587,011 Germany Oct.--25, 1933 

